Wrong. A perfect example of hyper-sensitivity leading to incorrect descriptions or conclusions.
"According to Dr David Pilgrim, author of several books on the history and cultural symbols of the Jim Crow era, the word picnic derives from the 17th century French word “pique-nique,” a term used to describe a social gathering in which attendees each contributed with a portion of food or another useful item ( here )."
The lynchings and murders were often done in a picnic-like atmosphere, to our shame. But that is not the origin of the word. It certainly did NOT originate with ‘Pick-a-’N*gg*r’.